The scourge of sexual violence is an issue finally gaining critical attention.

In January 2011, a taxi driver in a remote town in Kenya raped a 28-year-old hotel receptionist on her way to work. She immediately went to the hospital and reported the crime to the police. The taxi driver was initially convicted of rape, but three years later, a judge in Kenya’s High Court in Mombasa overturned the conviction. The judge didn’t dispute that the victim was forced to have sex, nor did she challenge the doctor’s corroborating evidence.

The judge tossed the case because prosecutors failed to analyze the DNA from the victim’s biological samples. According to the judge, “Such testing is necessary to prove a charge of rape conclusively.” The judge found the accused guilty of indecent assault – a lesser charge that reduced his prison time to three years—and fined him 30,000 Kenyan schillings – around $300.

That decision – which still stands as precedent in Kenya today – reflects the dangers of over-reliance on DNA evidence worldwide. The expectation that “science will prove all” can actually undermine justice for survivors of sexual violence.

There’s no doubt DNA technology in sexual violence cases has strengthened investigations and prosecutions. The technology allows police to collect a wider range of compelling evidence, and DNA may also connect a suspect to a crime scene. But specimens are only meaningful when they can be matched with a reference sample – which means that the suspect must have already been identified, making DNA evidence less relevant in cases of gang rape or conflict-related violence, where perpetrators are often unknown.

What’s more, DNA evidence can’t establish whether sexual contact was consensual – one of the most fiercely contested issues in these cases. And in many instances, biological specimens cannot be produced, for example, if the perpetrator used a condom, or if the survivor bathed after the assault or didn’t visit a clinic until several days afterward.

But a survivor should not be denied access to justice when there is no DNA evidence. The absence of DNA does not mean the crime did not occur, just as its presence should not lead a judge to conclude a crime did occur.

The case in Kenya suggests the globalization of the “CSI Effect” – a phenomenon where juries and judges won’t convict without the kinds of forensic evidence they see glamorized on television. Yet several studies on sexual assault show that most victims don’t report to health care facilities within three or four days of an attack, the optimal time to collect biological evidence. However, in parts of central and eastern Africa, transportation to health clinics can be difficult – in the Democratic Republic of the Congo, for example, poor roads, expensive fuel, and lack of access to a vehicle force survivors in rural areas to walk for several days to get treatment.

The expectation that “science will prove all” can actually undermine justice for survivors of sexual violence.

Furthermore, most health care providers in less developed regions have not been trained in collecting biological specimens, such as DNA, nor do they have the resources to adequately do so. Health care facilities in rural areas of even middle-income countries typically have limited or no access to rape kits. For those that do, many victims cannot afford the cost if personally charged for the DNA lab analysis. In some countries, including parts of the United States, a rape survivor may be required to pay between $500 and $1,500 for the analysis. And then there is the notorious delay in examining the kits. A lab in South Africa reported a backlog of 20,000 unanalyzed rape kits, and the reported numbers in the United States have reached a staggering 400,000 unexamined kits.

In Kenya, analysts in the country’s main crime lab lament that evidence frequently arrives degraded and contaminated due to poor collection, packaging, or delivery. On one visit, I saw the blade of a panga, a two-foot long bush knife, protruding from its paper wrapping. Samples often have little or no labeling or chain of custody documentation, often required by courts. Failure to adequately collect, preserve, and handle the evidence can destroy a case.

Kenya is not alone. Studies analyzing sexual assault cases around the globe show that when it comes to the way evidence is collected, documented, preserved, and managed, there is a widespread lack of training and competence among medical, law enforcement, and legal professionals. These studies also indicate an urgent need to address “rape myths” commonly held by first responders – that is, a tendency to question victims’ credibility and minimize the gravity of the crime.

Rather than investing in complex and often expensive technology, policymakers in countries like Kenya must prioritize rigorous training to enhance core competencies. Clinicians should obtain a survivor’s history, conduct a comprehensive physical and psychological evaluation, and document findings in standardized forms to ensure consistency and to more efficiently inform police investigations. That doesn’t require anything beyond know-how and a notepad.

But it’s not just investigators who need training. First responders must be trained to work to support survivors. Physicians for Human Rights and our partners in Kenya and the Democratic Republic of the Congo – doctors, nurses, police officers, lawyers, magistrates, and judges – have seen the extraordinary power of collaborating as a network to develop a standard medical intake form or chain of custody label, simple devices that have resulted in successful prosecutions.

DNA technology may offer judges a tempting means of moving beyond the thickets of conflicting testimony, but it’s no substitute for effective investigations and training. DNA evidence should never be required to prove that rape took place. It should instead be viewed as one more tool in advancing justice for victims of sexual violence.

The scourge of sexual violence is an issue finally gaining critical attention. But this case in Kenya should sound a cautionary note against placing unrealistic faith in technological quick fixes. DNA testing is no substitute for the slow, sedulous work of training across sectors and developing basic capacity within domestic legal systems. Nothing less than the full complement of these tools will allow countries to challenge the deeper culture of impunity that enables these crimes and to bring survivors the justice they deserve.

Karen Naimer directs the Program on Sexual Violence in Conflict Zones at Physicians for Human Rights, a New York-based advocacy organization that uses medicine and science to prevent severe human rights violations and mass atrocities.